This invention relates to an ejection seat and more particularly to an ejection seat having a blast protection system.
Ejection seats are commonly used in military aircraft where the risk of aircraft failure or combat damage is high. Ejection seats allow the aircrew to escape from stricken aircraft and typically provide a safe and reliable means of escape.
Ejection seats have long been fitted with arm and leg restraint systems which serve to secure the arms and legs of the aircrew in a safe position during ejection. During normal flight the aircrew's arms and legs must clearly be allowed to be free in order to control the aircraft. However, during ejection it is important to move the arms and legs of the aircrew into a safe position and secure the arms and legs into that position to avoid injuries which can be caused either by limbs flailing and hitting the side of the cockpit or as a result of the inertial forces which would be experienced by outstretched limbs. As the ejection seat leaves the aircraft, the occupant of the seat experiences wind blast due to the forward speed of the aircraft which will cause further limb flailing if the occupant's limbs are not restrained. As well as injuries to limbs, neck injuries and head injuries are also a hazard. Thus, some ejection seats provide neck restraint systems which secure the head of the aircrew into a safe position during ejection.
One major disadvantage of presently available arm and leg restraint systems and neck restraint systems is that the aircrew are required to don or manually connect themselves to the restraint systems. The difficulty of this task is compounded by the fact that the aircrew are likely to be wearing cumbersome NBC protective clothing. Assistance is therefore usually required in order for the aircrew to be properly connected to the restraint system.
During ejection, the combination of the aircrew and the ejection seat does not present a very aerodynamic profile and therefore suffers from a fairly high coefficient of drag. Thus, the lower the mass of the occupant of the ejection seat, the greater the deceleration which will be experienced during ejection. For this reason, lower mass occupants cannot safely be ejected at high speeds and the escape envelope of higher mass occupants is limited.
It is an object of the present invention to seek to ameliorate or overcome the problems associated with the aforementioned problems associated with ejection seats and restraint systems therefor.
Accordingly, one aspect of the present invention provides an ejection seat having a blast protection system comprising a blast screen stowed on the ejection seat and deployable to at least substantially envelop an occupant of the seat.
Preferably, the blast screen is inflatable.
Advantageously, the ejection seat has two sides and the inflatable blast screen is stowed along one side of the ejection seat for deployment across the front of the ejection seat from the one side toward the other side.
Conveniently, attachment means are provided to attach an edge of the inflatable blast screen to the other side of the ejection seat after deployment.
Preferably, a further inflatable blast screen is stowed along the other side of the ejection seat for deployment across the front of the ejection seat toward the one side.
Conveniently, attachment means are provided to attach an edge of the inflatable blast screen to an edge of the further inflatable blast screen.
Advantageously, the attachment means comprises a hook and loop fastening system.
Preferably, the blast screen is stowed toward the top of the ejection seat for deployment downwardly over the front of the ejection seat from the top of the ejection seat toward the bottom of the ejection seat.
Conveniently, the blast screen is stowed in a container attached to the ejection seat.
Advantageously, the container is provided with a slot through which the blast screen can be deployed.
Preferably, the container is provided with a pre-weakened area which is breakable upon deployment of the blast screen to allow the blast screen to burst through the pre-weakened area.
Conveniently, the blast screen comprises a canopy to enclose at least the upper body of the occupant.
Advantageously, the blast protection system incorporates an inflatable head cover, a portion of the head cover being inflatable between a headrest of the ejection seat and the occupant's head during deployment of the blast protection system.
Preferably, a further portion of the head cover inflates over the occupant's head.
Conveniently, the further portion of the head cover inflates downwardly and forwardly with respect to the ejection seat to initiate deployment of the blast screen over the seat occupant.
Advantageously, the head cover is attached to or comprises part of the blast screen.
Preferably, the blast screen is provided with a frame to provide rigidity to a bottom of the blast screen when the blast screen is deployed.
Conveniently, the frame is inflatable.
Alternatively, the frame is not inflatable.
Advantageously, the frame is pivotally mounted at one end to the seat and is stowed substantially against the seat.
Preferably, the blast screen is attached to the frame and is releasably attached to the seat.
Conveniently, the blast screen is attached to the head cover and the head cover is releasably attached to the seat.
Advantageously, inflation of the head cover initiates deployment of the blast screen.
Preferably, the blast screen includes an inflatable framework which defines the shape of the blast screen and enhances the rigidity thereof.
Conveniently, the inflatable framework comprises a plurality of inflatable ribs.
Another aspect of the present invention provides an ejection seat having a blast protection system comprising an inflatable head cover, a portion of the head cover being inflatable between a headrest of the ejection seat and the occupant's head during deployment of the blast protection system.